The sponge's airiness has other benefits, too: A titanium dioxide ceramic sponge can hold up to 50 times its weight in water. It can actually clean that water as well, reacting with sunlight to remove particles. In some modern water filtration technology, titanium dioxide removes contaminants from water in its powdered form, which is hard to reuse. But in the new sponge form, the compound can still break down an artificial dye in water after just 15 minutes under a light. After treatment, clean water can be wrung out, and the sponge can be used again.